int gcd(int a,int b)
{
    return a?gcd(b%a,a):b;
}
int lcm(int a,int b)
{
    return a*b/gcd(a,b);
}

int main()
{
    printf("%d\n",8==gcd(0,8));
    printf("%d\n",2==gcd(4,6));
    printf("%d\n",99==gcd(198,99));
    return 0;
}
